1. Field of the Application
The present application relates to a digital radio receiver system and method for switching from receiving a first broadcast service to an alternative broadcast service. The present invention also relates to a digital radio receiver system and method for scanning for broadcast services in a broadcast signal to generate an alternative broadcast service list for use in controlling the digital radio receiver system.
2. Description of the Related Art
When receiving broadcast services, such as OFDM broadcast services (for example DAB broadcast services), the receiver may occasionally lose the current signal being demodulated and decoded and need to select an alternative. Certain OFDM broadcast standards may provide signalling information to assist the receiver in identifying an alternative service.
For example, the DAB standard EN 300401 presents a mechanism of signalling (“Service Linking”) information to allow services to be conceptually linked together—either as “hard links” where the service content is identical, or as “soft links” where the services share some other relationship (most likely from the same broadcaster).
Service Following uses Service Linking information to maintain continuity of content. DAB standard TS 103 176 describes Service Following as “the term applied to maintaining the same audio or data content that the user has selected in spite of the varying reception conditions that occur”. It states that service following “provides information to allow precisely the same service to be followed”.
It is desirable by the user (and thus commercially advantageous to the manufacturer) for the receiver to identify, select and start demodulating and decoding a suitable alternative service as swiftly as possible.
A known solution to this is to include two radio tuners in the radio receiver as shown in FIG. 1. A first tuner 1a and demodulator 2a receive and demodulate the original broadcast service selected by the user, whilst the second radio tuner 1b and demodulator 2b tunes to other frequencies to select a suitable alternative service. However, this is a costly solution, as there are two tuners and demodulators.
We have appreciated the need for an alternative cost-efficient receiver design employing a single-tuner and single demodulator that uses a variety of techniques to select a suitable alternative service swiftly.